Question: Why are spacesuits so big?

Spacesuit have lots of layers and this makes them quite chunky; there are layers to protect the astronaut from the cold and heat, to cool them down, to keep the air in, keep the micro-meteorites out, provide power and oxygen- the suits are really little spacecraft that are people shaped.

I can just echo what Kirsty said: The fabric itself has lots of layers for protection. Then the backpack is full of life support systems – heaters/coolers, oxygen containers, batteries for the helmet lights, drinking water, etc.

It’s also not easy to put them on! Usually you need someone to help you out, unlike in most hollywood movies.